If you allow your visitors to post comments on your WordPress website, you should be using Akismet. This plugin identifies spam comments with remarkable accuracy, much like a junk mail filter for your email. Don’t think you’re going to get much spam on your website? You’re in for a big surprise. Unless you’re blocking the search engines from finding your website, you will get a lot of seemingly random traffic and spam comments, the vast majority of which come from automated programs. Over time, you will get more and more of it. But if you’re using Akismet, you won’t have to waste much time sorting through spam comments.
You will need to sign up for an Akismet API key at https://akismet.com/signup/. It can be free if you choose the “Personal site” option (they don’t check). But if you are getting a lot of traffic to your website, you should consider one of the paid options to improve Akismet’s performance on your website. After you sign up, you just need to activate the Akismet plugin and add your API key. There are a couple of configuration options, but most users can just leave the settings as they are. Akismet also keeps track of a number of statistics, such as how much spam it’s caught, legitimate comments, spam it’s missed, and false positives.
If you don’t want anyone to post comments on your website, it’s best to simply switch them off in the Settings > Discussion menu. You could also change various settings to improve the quality and administration of comments on your website. For example, you could choose to only allow registered users to comment, automatically allow a comment to be posted if you’ve approved a previous comment by that author, and you could set up spam filters that are triggered by specific keywords or IP addresses.